Equations / Root biomass
Guangzhou subtropical forest belowground biomass, Model 5 (DBH and wood density)
As printed (Section 2.4, Eq. 5)
In this library's units, ready to compute (kg)
Root biomass = exp(-2.644 + 1.136 * ln(D^2) + 0.936 * ln(rho))D- Diameter at breast height (1.3 m), cm
rho- Wood density (oven-dry mass / green volume), g/cm³
ln(B) = a + bln(DBH²) + cln(WD). Fitted in R (nlme) on ln-transformed biomass; the paper states no back-transform correction factor and none is applied. Aboveground biomass is above a 10 cm stump (stem, branches, leaves); belowground is the root system plus stump. The paper lists five models (1)-(5); model (2) (ln DBH²H) and (4) (ln DBH²WD) are not added here. Wood density WD is the stem basic density measured by water displacement (oven-dry mass over fresh volume). The diameter range of the belowground subsample is not stated, so none is given.
doi:10.3390/f10100862 · Open access · copy we read
(5) −2.644 ± 0.178 1.136 ± 0.025 0.936 ± 0.189 1.041 0.310 0.928 17.8 35.21 −4.67
(5) −2.644 ± 0.178 1.136 ± 0.025 0.936 ± 0.189 1.041 0.310 0.928 17.8 35.21 −4.67
for a total of 116 trees, including 24 species and 7 diameter classes
- Trees measured
- 116
- R²
- 0.928
- Method
- ln-ln regression (R, nlme)
- Where
- Fushan, about 26 km northeast of Guangzhou, Guangdong
- Last checked
- 2026-11-02
Shaded: the DBH range the model was fitted on. Other inputs held at the values above.
On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.
| Inputs | Expected | We get | From |
|---|---|---|---|
| D = 15, rho = 0.45 | 15.8 | 15.8 | Computed from the printed form hand-computed from the published form |
| D = 40, rho = 0.5 | 162.1 | 162.1 | Computed from the printed form hand-computed from the published form |
Related
- Guangzhou subtropical forest belowground biomass, Model 1 (DBH only) · Zhao et al. 2019 · DBH
- Guangzhou subtropical forest belowground biomass, Model 3 (DBH and height) · Zhao et al. 2019 · DBH + Height
- Guangzhou subtropical forest aboveground biomass, Model 1 (DBH only) · same paper · Aboveground biomass
- Guangzhou subtropical forest aboveground biomass, Model 3 (DBH and height) · same paper · Aboveground biomass
- Guangzhou subtropical forest aboveground biomass, Model 5 (DBH and wood density) · same paper · Aboveground biomass
- Guangzhou subtropical forest belowground biomass, Model 1 (DBH only) · same paper · Root biomass
- Guangzhou subtropical forest belowground biomass, Model 3 (DBH and height) · same paper · Root biomass
- Guangzhou subtropical forest branch biomass, Model 1 (DBH only) · same paper · Branch biomass
- Guangzhou subtropical forest leaf biomass, Model 1 (DBH only) · same paper · Foliage biomass
- Guangzhou subtropical forest stem biomass, Model 1 (DBH only) · same paper · Stem biomass